Thermo–Energetic Modelling and Operational Load Limits of a Solar Dryer for Chestnuts
Nicole Leonardo, Freddy J. Rojas, Celso De-La-Cruz Department of Engineering, Pontifical University Catholic of Peru, San Miguel, (Perú) 2026-06-27

Abstract

This study presents a thermoenergetic evaluation of a solar drying system for chestnuts, operating with an initial moisture content of 47% and a final moisture content of 20%. The system consists of a 1 m³ drying chamber coupled to a solar collector with a thermal efficiency of 45%, evaluated with an average solar irradiance of 656 W/m² and an ambient temperature of 26 °C.

The processed mass was varied between 2 and 40 kg to analyze energy performance and thermal stability. The specific energy consumption (SEC) decreased from 3.63 to 2.69 kWh/kg as the load increased, indicating better energy utilization at higher processing capacities. These values ​​are within the ranges reported for solar drying of agricultural products, confirming the system's energy suitability.

However, the internal temperature analysis showed a progressive decrease with increasing mass. For loads exceeding approximately 40 kg, the calculated temperature at a critical internal point decreased significantly, indicating an energy deficit under the fixed geometric configuration. This result reveals a thermal operating limit imposed by the chamber volume rather than the collector efficiency, highlighting the need to balance load, geometry, and available thermal energy in the design of a scalable solar dryer.

Key words: Solar drying, specific energy consumption (SEC), thermal stability, system scalability

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